This invention relates to improved display devices provided with a pictorial representation which is changed by opaque picture portions in transparent overlay areas.
Pictorial calendars heretofore have been primarily of the type wherein a single picture is displayed throughout the year, or wherein a number of separate pages each bear their own complete picture. Unlike these previous calendars, one aspect of this invention is directed to a calendar wherein a single basic picture is displayed throughout the year, but certain portions thereof are changed during the course of the year, preferably to present an appearance corresponding to the time period represented by the uppermost calendar page.
There have been display devices which utilize transparent overlay sheets which bear picture portions representing snowcovered scenic elements, anatomical features or cutaway views of mechanical or physical objects. In some instances, these overlay sheets have borne different picture portions on their opposite sides which are material elements of objects depicted on opposite leaves of a book.